Layer 1 protocols and technologies have evolved including Synchronous Optical Network (SONET)/Synchronous Digital Hierarchy (SDH) in the 1990s to Optical Transport Network (OTN) in the 2000s. SONET/SDH were synchronous protocols optimized for circuit switching and transmission. OTN evolved from SONET/SDH to provide transparency and support for Wavelength Division Multiplexing (WDM) as well as for optimized transmission of packet traffic. SONET, SDH, and OTN each have a rich suite of Operations, Administration, and Maintenance (OAM) functions and support for a wide range of services and applications. Conventionally, as OTN scales beyond 100 G (B100 G), there are emerging frameworks for Layer 1 functionality, namely Flexible OTN (FlexO or B100 G) initiatives in the International Telecommunication Union (ITU) and Flex Ethernet in the Optical Internetworking Forum (OIF).
Traditionally, Ethernet rates were defined in steps of 10×, i.e., 10 Mb/s, 100 Mb/s, 1 Gb/s (GbE), etc. There is a wrinkle in this 10× progression where 40 Gb/s Ethernet (40 GbE) was defined. Today, there are various Ethernet rates defined, including rates in-between established rates. IEEE 802.3 standards group is discussing 2.5 Gb/s, 5 Gb/s, 25 Gb/s and other various odd rates. Specifically, different rates are established for different applications, such as wireless applications, data center group applications, data center interconnections, etc. There is an expectation that different Ethernet rates will continue as new high-volume applications require optimized solutions. Specifically, router/switch equipment and optical transmission equipment are evolving at different rates. There is a desire to support simple transport of n× Ethernet streams across a faster interface. IEEE historically defines Ethernet rates (Media Access Control (MAC) layer) with projects that also define the Physical (PHY)/Physical Medium Dependent (PMD) rates; the MAC rates and PMD rates are tied and defined together. To address evolution in Ethernet and dissociate the MAC/client rate to the PHY/PMD, Flexible Ethernet has been proposed. Note, as described herein, the terms Flexible Ethernet, Flex Ethernet, and FlexE can be used interchangeably.
In transport applications, FlexE can be used to match the flexibility of optical transmission equipment. Specifically, optical transmission equipment (e.g., Dense Wave Division Multiplexing (DWDM)) is evolving to support variable modulation formats, Forward Error Correction (FEC) schemes, baud rates, etc. DWDM equipment can support a variable line rate with the same hardware, relying on configuration and provisioning. FlexE is based on Ethernet constructs, e.g., 64b/66b encoding, recognizing the primary client being transported is Ethernet. Note, the current scope of FlexE, as described in Implementation Agreement IA # OIF-FLEXE-01.0 “Flex Ethernet Implementation Agreement—Draft 1.1” (July 2015), the contents of which are incorporated by reference, is limited to interfacing applications (e.g., bonding, subrating, and channelization). However, it may be advantageous to leverage Flexible Ethernet to augment or even replace OTN and/or FlexO in some transport and switching applications.
Various techniques exist for various network protocols for authentication and encryption for secure communication sessions. For example, Internet Protocol Security (IPsec) (RFC 430x) provides secure Internet Protocol (IP) communications by authenticating and encrypting each IP packet of a communication session. IEEE 802.1AE is the IEEE MAC Security standard (also known as MACsec) which defines connectionless data confidentiality and integrity for media access independent protocols. Security has also been extended in a proprietary manner, to Layer 1 protocols such as proprietary OTN (“OTNSec”) or SONET bulk schemes. There are various disadvantages of IPSec, MACSec, and/or OTNSec. OTNSec is proprietary and, therefore, must be bookended and lacks interoperability. IPSec and MACSec cause packet inflation, i.e., an increase in packet size, so it decreases the effective throughput. These schemes also require complicated logic/circuitry with additional power and cost implications. Also, IPSec and MACSec only encrypt the payload, not the header. Further, with FlexE at Layer 1, there is an opportunity to provide bulk encryption at the FlexE layer, overcoming the aforementioned limitations as well as being used in combination with IPSec and/or MACSec.